FUELLING THE FUTURE
How to make a spaceship move faster than the speed of light
One of the most iconic abilities of the USS Enterprise is its ability to zip from one end of the galaxy to the other in mere moments using its fictitious warp drive. Human technology is currently nowhere near advanced enough to replicate the Enterprise’s warp drive. However, the theory behind building one has been around since the early 1990s. To achieve speeds faster than the speed of light, physics’ natural speed limit, theoretical physicist Miguel Alcubierre proposed that we must bend the fabric of space-time.
Space-time can be imagined as a sheet of rubber on which all matter sits, creating dips in the rubber relative to their masses. Alcubierre proposed that if space-time could be folded in front of a spaceship and then expanded behind it, the ship could travel much faster than the speed of light, achieving ‘warp speed’. This bending of space-time would theoretically continue to move in a wave and act as a conveyor belt, carrying the spaceship along it.
To achieve such space-time manipulation, Alcubierre suggested an enormous amount of negative mass, a phenomenon rarely created in laboratories and seen as vacuum energy in space. The amount of negative mass needed to facilitate Alcubierre’s warp drive would have to be equivalent to the mass of a huge star, distributed in a ring around a spacecraft. This hypothetical ring of negative mass would create a ‘warp bubble’, which would distort space-time and transport any spacecraft within it.
Although Alcubierre’s theory requires negative mass, recent research out of Göttingen University, Germany, offers a new area of physics for researchers to explore potential for warp power. In 2021, physicist Erik Lentz hypothesised that positive mass and energy could also provide the necessary requirements to construct a warp bubble. Instead of the solid ring of negative mass detailed in Alcubierre’s theory, Lentz proposes that layering rings of extremely dense fluid, similar to the composition of a neutron star’s interior, would yield the same result. With the ability to bend space-time, those inside the warp bubble could travel through space faster than the speed of light without breaking any physics laws. Much like the ability to walk freely in an aeroplane, a warp bubble would theoretically allow a spaceship and its crew to move around without feeling the effects of warp speed.
But there are several questions that remain unanswered about building a real-life warp-capable vessel, such as how to control its direction and distance, as well as how a ship would exit a warp bubble. In Star Trek, to fuel the warp drive and create enough energy to bend space-time, the USS Enterprise takes advantage of the annihilation reaction between matter – in the form of deuterium, a real-world isotope of hydrogen – and antimatter, which is regulated by a fictional crystal called dilithium. The ‘electro-
plasma’ energy released from this reaction creates the necessary warp bubble to manipulate space-time and move the ship. The biggest hurdle to overcome in using annihilation reactions for energy is producing enough antimatter to power a warp drive.
As the name suggests, antimatter is a mirrored and opposing version of normal matter. For example, an electron has a negative charge, so its antimatter partner has the same mass but an opposite positive charge, called a positron. In order to create antimatter, particle accelerators such as the Large
Hadron Collider fire high-speed particles at one another to release antimatter.
However, there are several physical issues with using antimatter as a fuel source. Firstly, the yield of its production is very low. The Fermi National Accelerator Laboratory (Fermilab) can only produce enough antimatter in an hour to power 1/1000th of a watt, and therefore 100,000 Fermilabs would be required to power a single light bulb. Due to the fact that antimatter annihilates when it comes in contact with regular matter, storing it is near impossible, as everything is made up of matter.
Despite these quantum woes, research into antimatter spacecraft is still ongoing. One of the latest advancements in antimatter propulsion is NASA’S proposal for a space probe that will travel all the way across our stellar neighbourhood to a relatively nearby star 4.2 light years away called Proxima Centauri, which will be done using an annihilation accelerator. But until scientists can successfully mass produce and store antimatter, powering a spacecraft that resembles the Enterprise remains firmly in the realm of science fiction.
“Despite quantum woes, research into antimatter spacecraft is still ongoing”